Anastomosis devices

ABSTRACT

An implantable medical device for connecting tissue layers, such as connecting tubular tissues to create an anastomosis, includes a single elongate member and a covering material. The devices provided may also be used for other purposes including, but not limited to, partially or fully occluding openings in tissue, temporarily or permanently holding generally planar layers of tissue together, aneurysm repair, and the like.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.14/818,800, filed Aug. 5, 2015, now U.S. Pat. No. 10,194,914, issuedFeb. 5, 2019, which claims the benefit of U.S. Provisional Application62/037,363, filed Aug. 14, 2014 both of which are incorporated herein byreference in their entireties for all purposes.

FIELD

This document relates to implantable medical devices, and moreparticularly, to implantable devices for connecting tubular tissues tocreate an anastomosis.

BACKGROUND

An anastomosis is a surgical connection between two tubular tissuestructures, such as blood vessels or intestines. For example, when aportion of an intestine is resected, the resulting two ends can be sewnor stapled together (anastomosed), using an intestinal anastomosisprocedure. This procedure can restore intestinal continuity after theresection of a bowel portion, or to bypass a portion of unresectablediseased bowel.

Portions of bowel may be resected for various reasons including, but notlimited to: bowel gangrene due to vascular compromise caused bymesenteric vascular disease, prolonged intestinal obstruction,intussusceptions, malignancy conditions, benign conditions (e.g.,intestinal polyps, intussusception, roundworm infestation withintestinal obstruction), infections (e.g., tuberculosis complicated withstricture or perforation), traumatic perforations, inflammatory boweldisease, ulcerative colitis, and Crohn's disease. Bypass of unresectablediseased bowel may be needed in situations including, but not limitedto: locally advanced tumors causing luminal obstruction, metastaticdisease causing intestinal obstruction, poor general condition orcondition that prevents major resection, and various pediatricconditions.

A circulatory anastomosis is a connection (an anastomosis) between twoblood vessels, such as between arteries (arterio-arterial anastomosis),between veins (veno-venous anastomosis), or between an artery and a vein(arterio-venous anastomosis).

Anastomoses can be created in various manners including, but not limitedto: end-to-end, end-to-side, and side-to-side anastomoses. Often,suturing is used to create such anastomoses.

SUMMARY

This document provides implantable medical devices. For example, thisdocument provides implantable devices for connecting tissue layers,including connecting tubular tissues to create an anastomosis. Thedevices provided may also be used for other purposes including, but notlimited to, partially or fully occluding openings in tissue, temporarilyor permanently holding generally planar layers of tissue together,aneurysm repair, and the like.

One embodiment of the invention relates to a medical device for creatingan anastomosis between a first body conduit and a second body conduit.The medical device includes (1) a frame that includes an elongate memberand (2) a covering material. The elongate member defines (1) a firstapposition portion configured to conform to a geometry of a first tissuesurface of the first body conduit and to provide an apposition forceagainst the first tissue surface, (2) a second apposition portionconfigured to conform to a geometry of a second tissue surface of thesecond body conduit and to provide an apposition force against thesecond tissue surface, and (3) a central portion disposed between thefirst apposition portion and the second apposition portion, the centralportion defining a lumen therethrough. The covering material may bedisposed on at least a portion of the central portion. Additionally, thecovering material is configured to allow material to flow through thelumen and between the first body conduit and the second body conduit.The elongate member is wound in a pattern where (1) the elongate memberdefines a first feature, (2) the elongate member traverses the centralportion, (3) the elongate member defines a second feature, (4) theelongate member traverses the central portion and (5) the elongaterepeats the pattern such that a plurality of first features and aplurality of second features is formed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the disclosure and are incorporated in and constitute apart of this specification, illustrate embodiments, and together withthe description serve to explain the principles of the disclosure.

FIG. 1A is a perspective view of a wire frame of an example anastomosisdevice in a contracted configuration;

FIG. 1B is a side view of the wire frame of FIG. 1A in a contractedconfiguration;

FIG. 2 is an end view of the wire frame of FIG. 1A;

FIG. 3A is a perspective view of the wire frame of FIG. 1A in anextended configuration;

FIG. 3B is a side view of the wire frame of FIG. 1A in an extendedconfiguration;

FIG. 4A is a side view of an example anastomosis device in a contractedconfiguration and including a covering material disposed on the centrallumen portion of the anastomosis device;

FIG. 4B is a side view of the anastomosis device of FIG. 4A in anextended configuration;

FIGS. 5A-5E are a series of illustrations depicting an exampledeployment process of an anastomosis device in accordance with someembodiments;

FIG. 6A is a perspective view of a portion of a wire winding mandrelthat can be used to create the wire frame of FIG. 1A; and

FIG. 6B is perspective view of a complete wire winding mandrel that canbe used to create the wire frame of FIG. 1A.

DETAILED DESCRIPTION

Persons skilled in the art will readily appreciate that various aspectsof the present disclosure can be realized by any number of methods andapparatus configured to perform the intended functions. It should alsobe noted that the accompanying drawing figures referred to herein arenot necessarily drawn to scale, but may be exaggerated to illustratevarious aspects of the present disclosure, and in that regard, thedrawing figures should not be construed as limiting.

In reference to FIGS. 1A, 1B, and 2, a frame 100 of an exampleanastomosis device includes an elongate member 110. The elongate member110 is configured to form a first apposition portion 120, a centralportion 130, and a second apposition portion 140. The central portion130 is disposed between the first apposition portion 120 and the secondapposition portion 140. In some embodiments, the central portion 130defines a lumen 132 that extends between the first apposition portion120 and the second apposition portion 140. The frame 100 is shown in acontracted configuration. In some embodiments, the contractedconfiguration is the configuration that the frame 100 naturally exhibitsin the absence of external forces acting upon the frame 100.

The first and second apposition portions 120 and 140 are configured toengage one or more layers of tissue therebetween, and to provideapposition forces against the tissue surfaces. The apposition forcesprovided by the first and second apposition portions 120 and 140 canprovide attachment of the frame 100 to the tissue and migrationresistance such that the frame 100 can reliably remain positioned at atarget site in a patient as desired. In some embodiments, each of thefirst and second apposition portions 120 and 140 are configured to form,in a general sense, discs that contact tissue surfaces.

In some embodiments, the lumen 132 provides an anastomosis passageway ortunnel through which materials can pass. In some embodiments, the frame100 is configured to be a sealing device and no lumen 132 is provided,or the lumen 132 is occluded by other material such as a coveringmaterial.

In some embodiments, the elongate member 110 comprises a singlecontinuous wire. As will be described further below in reference toFIGS. 6A and 6B, the single continuous wire can be bent using a mandrelto form the frame 100.

The elongate member 110 can comprise a variety of materials. Theelongate member 110 may be elastomeric, metallic, a spring wire, a shapememory alloy wire, a super-elastic alloy wire, or combinations andsub-combinations thereof, to name a few general examples. In fact, anytype of elongate member 110 that is suitably biocompatible, flexible,and resilient can generally be used for the anastomosis devices providedherein. For example, the elongate member 110 can comprise nitinol(NiTi), L605 steel, stainless steel, polymeric materials, or any otherappropriate biocompatible material, including combinations andsub-combinations of materials. In some embodiments, bioresorbable orbioabsorbable materials may be used, including, for example, abioresorbable or bioabsorbable polymer. In some such embodiments, theelongate member 110, or portions thereof, may eventually dissolve. Insome embodiments, the elongate member 110 is fully or partially coatedto facilitate a biological reaction, such as, but not limited to,endothelial cell attachment, endothelial cell migration, endothelialcell proliferation, and resistance to or promotion of thrombosis.

It should be clear that suitable materials for the elongate member 110include a variety of metallic shape memory materials and super-elasticalloys. Shape memory refers to the ability of a material to revert to anoriginally memorized shape after plastic deformation by heating above acritical temperature. Super-elasticity refers to the ability of amaterial to deform under strain to a very large degree, without havingthis deformation become permanent. For example, the super-elasticmaterials included in the frames of some anastomosis device embodimentsprovided herein are able to withstand a significant amount of bendingand flexing and then return to the frame's original form withoutdeformation. Some metallic shape memory materials used in theanastomosis devices are described in U.S. Pat. Nos. 3,174,851;3,351,463; and 3,753,700, all of which are hereby incorporated byreference in their entireties. In some embodiments, suitable shapememory and super-elastic materials include various stainless steelswhich have been physically, chemically, and otherwise treated to producehigh springiness, metal alloys such as cobalt chrome alloys (e.g.,ELGILOY™), platinum/tungsten alloys, and the NiTi alloys.

The super-elastic properties of NiTi make it a suitable material for theelongate member 110 of some embodiments of the anastomosis devicesprovided herein. NiTi elongate members 110 can be heat-set into adesired shape such that the NiTi elongate member 110 will tend toself-expand from a low-profile delivery configuration into the desiredshape when deployed from a delivery sheath to a target site within abody.

In some embodiments, the elongate member 110 can be treated in variousways to increase the radiopacity of the elongate member 110 for enhancedradiographic visualization. In some embodiments, the elongate member 110is at least partially a drawn-filled type of NiTi containing a differentmaterial at the core, such as a material with enhanced radiopacity. Insome embodiments, the elongate member 110 has a radiopaque cladding orplating on at least portions of the elongate member 110. In someembodiments, one or more radiopaque markers are attached to the elongatemember 110 (and/or to a covering material that is attached to theelongate member 110).

In some embodiments, the diameter or thickness of the elongate member110 is within a range of about 0.1 mm to about 1.50 mm, but in someembodiments an elongate member 110 having smaller or larger diameterscan be used. In some embodiments, the diameter of thickness of theelongate member 110 is within a range of about 0.2 mm to about 0.5 mm.Notwithstanding, it should be clear that the elongate member 110, andthe elongate members of other anastomosis devices provided herein, canhave any suitable size or diameter.

In some embodiments, the elongate member 110 has a consistent diameteralong the length of the elongate member 110. In some embodiments, one ormore portions of the elongate member 110 are diametrically tapered orotherwise inconsistent in diameter. In some embodiments, the elongatemember 110 may be formed using a center-less grinding technique, suchthat the diameter of the wire varies along the length of the elongatemember 110. The elongate member 110 may have a round cross-sectionalshape or may have a cross-sectional shape that is not round, such as arectangle or other polygon. Examples of other cross-sectional shapesthat the elongate member 110 may have include a square, oval, rectangle,triangle, D-shape, trapezoid, or irregular cross-sectional shape formedby a braided or stranded construct. In some embodiments, the elongatemember 110 may comprise a flat wire. In some embodiments, a combinationof such various types of elongate member 110 are used in an anastomosisdevice. While in some embodiments the elongate member 110 of the devicehas a uniform cross-sectional shape and size, in some embodiments, someportions of the elongate member 110 have a different cross-sectionalshape and/or size than other portions of the elongate member 110.

The elongate member 110 of the anastomosis devices provided herein mayexhibit, for example, beneficial fatigue resistance and elasticproperties. In some embodiments, the elongate member 110 allows theanastomosis devices to be elastically crushed, folded, and/or collapsedinto a low-profile configuration for containment within a lumen fortranscatheter or endoscopic/thorascopic delivery, and to self-expand toan operative size and configuration once positioned at a desired targetsite within a body and deployed from the lumen.

In some embodiments, the elongate member 110 may include one or morefixation elements (e.g., anchors, barbs, protrusions, atraumaticmembers, and/or penetrating members, and combinations thereof). In someembodiments, such fixation elements advantageously reduce or inhibit insitu migration of the anastomosis devices after deployment to a targetsite within a body.

Still referring to FIGS. 1A, 1B, and 2, in some embodiments the firstand second apposition portions 120 and 140 include multiple featuresthat are configured to contact a surface of a tissue, and to provide anapposition force to the tissue surface. For example, in the depictedembodiment the one or more features of the first and second appositionportions 120 and 140 include elongate wire loops 122 and 142respectively (such wire loops may also be referred to herein as fingersor petals). While in this embodiment, the first and second appositionportions 120 and 140 each include six wire loops 122 and 142, in someembodiments more or fewer than six wire loops 122 and 142 are included.For example, in some embodiments one, two, three, four, five, seven,eight, nine, ten, eleven, twelve, or more than twelve wire loops 122 and142 are included in the first and second apposition portions 120 and140.

While in the depicted embodiment, the wire loops 122 and 142 of thefirst and second apposition portions 120 and 140 are generally ovular inshape, it should be understood that an ovular shape is not required. Forexample, in some embodiments some or all of the wire loops 122 and/or142 can be circular, triangular, linear, rectangular, diamond-shaped,and the like, and combinations thereof. For example, in some embodimentssome or all of the wire loops 122 and/or 142 can have a first linearportion that projects radially from the central portion 130 and that iscontiguous with a second diamond-shaped portion at the free end of thewire loops 122 and/or 142. Other combinations and sub-combinations ofshapes are also envisioned.

While in the depicted embodiment the shape and size of all of theindividual wire loops 122 and 142 are generally uniform, it should beunderstood that such uniformity is not a requirement. For example, insome embodiments one or more of the wire loops 122 can be shaped orsized differently from one or more other wire loops 122 of the sameanastomosis device. Similarly, in some embodiments one or more of thewire loops 142 can be shaped or sized differently from one or more otherwire loops 142 of the same anastomosis device. Further, the size and/orshape of some or all of the wire loops 122 can be different from thesize and/or shape of some or all of the wire loops 142.

In some embodiments, some or all of the individual wire loops 122 and142 are configured to independently bear loads associated with tissuesurface contact. That is, in some embodiments individual ones of thewire loops 122 and/or 142 can be independently deflected in accordancewith the topography of the tissue surface without imparting asubstantial force to any other ones of the wire loops 122 and/or 142. Insome embodiments, this feature can allow each of the wire loops 122and/or 142 to provide an appositional force even though the tissuesurface topography is not planar. Hence, in some embodiments the firstand second apposition portions 120 and 140, or portions thereof, areconfigured to be highly conformable to irregular tissue surfaces. Insome embodiments, portions of some or all of the individual wire loops122 and/or 142 may abut or overlap with adjacent wire loops 122 and/or142. In some such embodiments, some movements of the wire loops 122and/or 142 may induce forces on one or more adjacent wire loops 122and/or 142.

The elongate member 110 also forms the generally cylindrical centralportion 130 (also referred to herein as the helical portion or tunnelportion). In some embodiments, the elongate member 110 is configuredsuch that the central portion 130 is comprised of one or more segmentsof a helix. The one or more segments of a helix, when combined together,form the generally cylindrical central portion 130. As will be describedfurther below, a generally fluid impermeable covering material can bedisposed on the central portion 130 in some embodiments. The diameter ofthe central portion 130 can be made in any size as desired in order tosuit the intended use of the anastomosis device.

While in some embodiments the central portion 130 is generallycylindrical, such a shape is not required. In some embodiments, some orall of the central portion 130 may have a cross-sectional shape such as,but not limited to, an elliptical cross-section, a polygonalcross-section, and other shapes. In some embodiments, the diameter ofthe lumen 132 is uniform along its entire length. In some embodiments,the diameter of the lumen 132 varies along its length. For example, insome embodiments the central portion 130 defines a lumen 132 that isfrustoconical, to provide one such example embodiment of a lumen 132with an inconsistent diameter.

In some embodiments, the elongate member 110 comprises a singlecontinuous member that is formed in a pattern to define the firstapposition portion 120, the central portion 130, and the secondapposition portion 140. For example, in the depicted embodiment the windpattern of the elongate member 110 can be described as follows. First,the elongate member 110 forms an individual wire loop 122 of the firstapposition portion 120. After forming the individual wire loop 122, theelongate member 110 traverses the central portion 130 along a helicalpath in a direction away from the first apposition portion 120 andtoward the second apposition portion 140. After traversing the centralportion 130 along the helical path, the elongate member 110 forms anindividual wire loop 142 of the second apposition portion 140. Afterforming the individual wire loop 142, the elongate member 110 traversesthe central portion 130 along a helical path in a direction away fromthe second apposition portion 140 and toward the first appositionportion 120. Then the pattern is repeated so as to form another wireloop 122 and another wire loop 142, and so on, until the entire firstapposition portion 120, central portion 130, and second appositionportion 140 have been fully formed. In some embodiments of theanastomosis devices provided herein, the aforementioned wind pattern, ormany other types of wind patterns, can be used to create the frames forthe anastomosis devices.

As described above, in some embodiments the elongate member 110 is asingle continuous element. Accordingly, the elongate member 110 includestwo free ends or termini. In some embodiments, the two free ends of theelongate member 110 can be conjoined such that the elongate member 110forms a closed wind pattern (i.e., a continuous loop). The free ends ofthe elongate member 110 can be joined together using a variety oftechniques including, but not limited to bonding, welding (e.g., laserwelding), gluing, using a sleeve coupling, and the like, andcombinations thereof. In some embodiments, a butt joint is used to jointhe free ends of the elongate member 110. In some embodiments, othertypes of joints can be used to join the free ends of the elongate member110, including but not limited to, an overlap joint, a twist joint, acrimp joint, and the like, and combinations thereof. The free ends canbe conjoined prior to or after heat-setting (in those embodiments thatuse a heat-setting process). In some embodiments, the free ends are notconjoined.

Referring to FIG. 1B in particular, the frame 100 defines a longitudinalaxis 102 through the center of the lumen 132. While in some embodimentsthe wire loops 122 of the first apposition portion 120 are generallyparallel with the wire loops 142 of the second apposition portion 140,in some embodiments some or all of the wire loops 122 of the firstapposition portion 120 and some or all of the wire loops 142 of thesecond apposition portion 140 are not parallel. For example, in someembodiments the distance between some or all of the free ends of thewire loops 122 and 142 is less than the distance between the wire loops122 and 142 near the central portion 130. In some embodiments, such aconfiguration provides an increased level of apposition force at theouter radius of the frame 100 as compared to nearer to the centralportion 130. In some embodiments, the increased level of appositionforce at the outer radius of the frame 100 can, in turn, facilitateconformance by the frame 100 to a significantly non-planar and irregulartissue surface. In some embodiments, to increase the level of appositionforce provided by the frame 100 further, the distance between the freeends of the wire loops 122 and 142 can be reduced to essentially zero.In some embodiments, to increase the apposition force provided by theframe 100 still further, the wire loops 122 and 142 can intersect orcross over each other.

When the frame 100 is in its contracted configuration, as shown in FIG.1B, the central portion 130 has a longitudinal length ‘x.’ In thedepicted embodiment, when the frame 100 is in its contractedconfiguration, essentially no space exists between adjacent helicalportions of elongate member 110 that make up the central portion 130. Insome embodiments, when the frame 100 is in its contracted configuration,some space exists between adjacent helical portions of elongate member110 that make up the central portion 130.

The longitudinal length ‘x’ can be selected by adjusting various designfeatures of the frame 100. In a first example, the cross-sectional size(e.g., diameter) of the elongate member 110 can affect the length ‘x.’In general, the larger the diameter of the elongate member 110, thelonger the longitudinal length ‘x.’ In a second example, having greaternumbers of wire loops 122 and 142 also increases the longitudinal length‘x.’ That is the case because having greater numbers of wire loops 122and 142 results in correspondingly more helical portions of elongatemember 110 in the central portion 130. In a third example, having spacebetween one or more of the helical portions of elongate member 110 inthe central portion 130 also increases the longitudinal length ‘x.’

Referring now to FIGS. 3A and 3B, the frame 100 is shown in alongitudinally extended configuration (as compared to FIGS. 1A and 1B)such that the length of the central portion 130 has increased fromdistance ‘x’ to a longer distance ‘y.’ Such longitudinal extension ofthe depicted embodiment requires the application of a longitudinaltensile force to the frame 100. In other words, when the first andsecond apposition portions 120 and 140 are forced longitudinally awayfrom each other the frame 100 is extended. The extension of the frame100 results in the creation of spaces between the helical portions ofelongate member 110 in the central portion 130. In some embodiments, thecentral portion 130 can be considered analogous to an extension spring.Therefore, in general the greater the distance ‘y,’ the greater theapposition forces delivered by the first and second apposition portions120 and 140.

As the frame 100 is extended from its contracted configuration, thediameter of the lumen 132 changes comparatively little. That is the casebecause the helical portions of elongate member 110 in the centralportion 130 are almost perpendicular to the longitudinal axis 102 whenthe frame 100 is in its contracted configuration. Therefore, as theframe 100 is extended, the resulting movements of the helical portionsof elongate member 110 in the central portion 130 result in asubstantially greater extension of the frame 100 than a diametricalreduction of the lumen 132. In some embodiments, such a capability offrame 100 to change in longitudinal length with little change in thelumen 132 diameter is advantageous for maintaining consistent patency oflumen 132 while accommodating variable tissue thicknesses.

Referring now to FIGS. 4A-4B, an anastomosis device 400 includes theframe 100 and a covering material 210 (which may also be referred toherein as a sealing material). The covering material 210 can be disposedon and/or attached to one or more portions of the central portion 130 ofthe frame 100. In some embodiments, the covering material 210 canadditionally, or alternatively, be disposed on one or both of the firstand second apposition portions 120 and 140, or portions thereof.

In some embodiments, the covering material 210 is disposed on at leastportions of the exterior of the central portion 130. In someembodiments, the covering material 210 is disposed on at least portionsof the interior of the central portion 130. In some embodiments, thecovering material is disposed on at least portions of both the interiorand exterior of the central portion 130. The covering material 210 can,in some embodiments, enhance the tubular integrity of the lumen 132(refer to FIGS. 1A-3B) so that the lumen 132 can function as ananastomosis conduit. Alternatively, the covering material 210 can beapplied to the frame 100 so as to fully or partially occlude the lumen132. In such cases, the resulting device can be used to seal an openingin a tissue (e.g., an aperture, puncture, tear, burst aneurysm, aresection area, and the like).

In some embodiments, the covering material 210 is made of a membranousmaterial that inhibits or reduces passage of blood and/or other bodilyfluids and materials through the covering material 210 itself. In someembodiments, the covering material 210 has a material composition andconfiguration that inhibits or prevents tissue ingrowth and/orendothelialization into the covering material 210. Some such embodimentsthat are configured to inhibit or prevent tissue ingrowth and/orendothelialization can be more readily removed from the patient at afuture date if so desired. In some embodiments, the covering material210, or portions thereof, has a microporous structure that provides atissue ingrowth scaffold for durable sealing and/or supplementalanchoring strength of the sealing device.

In some embodiments, the covering material 210 comprises afluoropolymer, such as an expanded polytetrafluoroethylene (ePTFE)polymer. In some embodiments, the covering material 210 comprises apolyester, a silicone, a urethane, another biocompatible polymer,polyethylene terephthalate (e.g., Dacron®), bioabsorbable systems,copolymers, or combinations and subcombinations thereof.

In some embodiments, the covering material 210, or portions thereof, ismodified by one or more chemical or physical processes that enhance oneor more properties of the materials. For example, in some embodiments, ahydrophilic coating is applied to the covering material 210 to improvethe wettability and echo translucency of the material 210. In someembodiments the covering material 210, or portions thereof, is modifiedwith chemical moieties that facilitate one or more of endothelial cellattachment, endothelial cell migration, endothelial cell proliferation,and resistance to or promotion of thrombosis. In some embodiments thecovering material 210, or portions thereof, is modified with one or morecovalently attached drug substances (e.g., heparin, antibiotics, and thelike) or impregnated with the one or more drug substances. The drugsubstances can be released in situ to promote healing, reduce tissueinflammation, reduce or inhibit infections, and to promote various othertherapeutic treatments and outcomes. In some embodiments the drugsubstance is a corticosteroid, a human growth factor, an anti-mitoticagent, an antithrombotic agent, a stem cell material, or dexamethasonesodium phosphate, to name some examples. In some embodiments, apharmacological agent is delivered separately from the covering material210 to the target site to promote tissue healing or tissue growth.

Coatings and treatments may be applied to the covering material 210before or after the covering material 210 is joined or disposed on theframe 100 of the anastomosis device 400. Additionally, one or both sidesof the covering material 210, or portions thereof, may be coated. Insome embodiments, certain coatings and/or treatments are applied to thematerial(s) located on some portions of the anastomosis device 400, andother coatings and/or treatments are applied to the material(s) locatedon other portions of the anastomosis device 400. In some embodiments, acombination of multiple coatings and/or treatments are applied to thecovering material 210, or portions thereof. In some embodiments, certainportions of the covering material 210 are left uncoated and/oruntreated.

In some embodiments, a first portion of the covering material 210 isformed of a first material and a second portion of the covering material210 is formed of a second material. In some embodiments, the coveringmaterial 210 is comprised of multiple layers of materials, which may bethe same or different materials. In some embodiments, portions of thecovering material 210 have one or more radiopaque markers attachedthereto to enhance in vivo radiographic visualization of the anastomosisdevice 400.

In some embodiments, one or more portions of the covering material 210are attached to the elongate member 110, such as in the central portion130. The attachment can be accomplished by a variety of techniques, suchas by stitching the covering material 210 to the elongate member 110, byadhering the covering material 210 to the elongate member 110, bylaminating multiple layers of the covering material 210 to encompass theelongate member 110, by using clips or barbs, or by other suchtechniques or combinations thereof. In some embodiments, the elongatemember 110 of the frame 100, or portions thereof, may be coated with abonding agent, for example fluorinated ethylene propylene (FEP) or othersuitable adhesive for bonding the covering material 210 to the elongatemember 110. The adhesive may be applied through contact coating, powdercoating, dip coating, spray coating, or any other appropriate means. Theframe 100 thereby provides a supportive structural framework for thecovering material 210 that may be otherwise relatively flaccid.

In FIG. 4A, the frame 100 is depicted in its contracted configuration.In FIG. 4B, the frame 100 is in an example extended configuration. Thecovering material 210 can adapt to such changing configurations of theframe 100, i.e., both the contracted and extended configurations.Additionally, as will be described further below, the covering material210 can adapt to a low-profile delivery configuration in which the frame100 is greatly elongated.

The covering material 210 can adapt to changes in the length and/ordiameter of the central portion 130 in a variety of manners. In a firstexample, the covering material 210 can be elastic such that the coveringmaterial 210 can stretch to accommodate changes in the length and/ordiameter of the central portion 130. In a second example, the coveringmaterial can include slackened material in the contracted configurationthat becomes less slackened or totally unslacken as the central portion130 is extended and/or enlarged. In a third example, the coveringmaterial 210 can include folding portions that are folded in thecontracted configuration and less folded or totally unfolded as thecentral portion 130 is extended and/or enlarged. In some embodiments,combinations of such techniques, and/or other techniques can be usedwhereby the covering material 210 can adapt to changes in the lengthand/or diameter of the central portion 130.

As will be described further below, the configuration of the anastomosisdevice 400 (and other anastomosis device embodiments provided herein),as well as the flexibility and elasticity of the elongate member 110,make the anastomosis device 400 capable of transcatheter deployment.That is, in some embodiments the anastomosis device 400 can beelastically collapsed to a low-profile configuration for temporarycontainment within a lumen of a delivery catheter or sheath. To deploythe anastomosis device 400, the sheath containing the anastomosis device400 in the low-profile configuration is inserted into the body of apatient and directed to a target site—typically using radiographicvisualization (e.g., fluoroscopy), or using endoscopic optics for directvisualization. At the target site, the anastomosis device 400 is causedto emerge and become liberated from the sheath (e.g., using a pushercatheter), after which the anastomosis device 400 self-expands, or iscaused to expand, to an enlarged configuration. For example, FIG. 1Ashows the frame 100 of the anastomosis device 400 in the enlargedconfiguration that the frame 100 will naturally tend to seek in theabsence of external constraining forces, such as those forces from adelivery sheath.

It should be understood that when the anastomosis device 400 is deployedin a patient's body, there will typically be constraining forces appliedto the anastomosis device 400, such as from the tissue and the tissueaperture(s) in which the anastomosis device 400 resides. Because ofthose constraining forces, the shape of the anastomosis device 400within the body may tend to be different than the shapes shown in thefigures of the instant specification. Said another way, when theanastomosis device 400 is deployed within the body, the anastomosisdevice 400 will try to expand to its natural fully enlargedconfiguration, but the anastomosis device 400 may be constrained by thecontours of the anatomy at the target site. In such circumstances, theshape of the anastomosis device 400 will tend to conform to the contoursof the anatomy.

After the original deployment of the anastomosis device 400 at thetarget site, the contours of the anatomy may change over time. Forexample, if the anastomosis device 400 is deployed within the GI tract,the peristaltic wave motion of the intestines may change the contours ofthe anatomy at the target site. In that circumstance, the flexibilityand elasticity of the anastomosis device 400 can allow the elongatemember 110 to adapt in shape to facilitate resilient ongoing contactbetween the anastomosis device 400 and the surrounding tissue.

Referring now to FIGS. 5A-5E, an example anastomosis device system 500can be used to deploy an example anastomosis device 530 to create aside-to-side anastomosis between two body conduits 540 and 550. Theconduits 540 and 550 are shown in longitudinal cross-section to allowbetter visualization of the deployment of the anastomosis device 530 bythe anastomosis device system 500. The conduits 540 and 550 may beintestines or blood vessels, for example. In some embodiments, theanastomosis device 530 is configured to be implanted such that a patentpassageway or tunnel is created between the conduits 540 and 550. Insome implementations, the anastomosis device 530 is implanted on atemporary basis while the tissues of the body conduits 540 and 550 growtogether to form a tissue anastomosis, and thereafter the anastomosisdevice 530 is retrieved/removed from the implant site. In someimplementations, the anastomosis device 530 is intended to remainimplanted for a longer term or permanently.

The body conduits 540 and 550 can be prepared for the anastomosis bysurgically closing the ends of the body conduits 540 and 550, and thenconnecting the closed end portions of the body conduits 540 and 550 inan overlapping arrangement. The anastomosis device system 500 canapproach the overlapped portion of the body conduits 540 and 550 throughone of the body conduits 540 or 550. For example, in someimplementations the anastomosis device system 500 can approach thetarget implant site endoscopically.

The anastomosis device system 500 can include a sheath 510, an incisiondevice 520, and the anastomosis device 530. The anastomosis devicesystem 500 can be manipulated/operated externally of the patient's bodyby a clinician operator. In other words, the clinician operator canremotely operate the anastomosis device system 500 to perform the stepsillustrated in FIGS. 5A-5E in a percutaneous fashion through an incisionto the patient's skin, or through a natural patient orifice. In someimplementations, fluoroscopy or other imaging modalities can be usedduring the deployment process to assist the clinician operator toimplant the anastomosis device 530 in the target location as desired.

In FIG. 5A, the delivery sheath 510 approaches the target site throughthe body conduit 550. It should be understood that the anastomosisdevice 530 is positioned within a lumen of the sheath 510 during thisstep. Within the lumen, the anastomosis device 530 is configured in alow-profile configuration. To attain the low-profile configuration, theframe 100 (e.g., refer to FIG. 3B) can be elastically deflected andextended so that most portions of the elongate member 110 aresubstantially parallel with the longitudinal axis 102. In some cases,one or more portions of the anastomosis device 530 can be folded one ormore times for containment within the sheath 510. In some embodiments,the sheath 510 has about a 15 Fr. (5 mm) outer diameter. However, insome embodiments, sheaths that are smaller or larger than 15 Fr. can beused. For example, sheaths that have outer diameters of 6 Fr., 7 Fr., 8Fr., 9 Fr., 10 Fr., 11 Fr., 12 Fr., 13 Fr., 14 Fr., 16 Fr., 17 Fr., 18Fr., 19 Fr., 20 Fr., and larger than 20 Fr., can be used in someembodiments.

In FIG. 5B, the incision device 520 has been extended from the distaltip of the sheath 510, and the incision device 520 is being used tocreate an opening 560 through the walls of both body conduits 540 and550. The incision device 520 can be a variety of different types ofdevices including, but not limited to, a scalpel, an electrocauterydevice, a surgical scissors, and the like. In some embodiments, theincision device 520 is separate from the sheath 510.

In FIG. 5C, the incision device 520 has been retracted, and theanastomosis device 530 is in the process of being expelled from thesheath 510 by the actions of the clinician operator. For example, insome embodiments, the clinician operator can expel the anastomosisdevice 530 from the sheath 510 by advancing a pusher catheter that islocated within the sheath and that can push the anastomosis device 530distally in relation to the sheath 510. During this step, the clinicianoperator positions the sheath 510 so that the leading portion of theanastomosis device 530 extends through the opening 560 and into thelumen of the body conduit 540. In some embodiments, one or moreradiopaque markers are located on the anastomosis device 530 so thatfluoroscopy can be used to assist the clinician to visually position thesheath 510 and/or the anastomosis device 530 as desired.

In FIG. 5D, the clinician operator has advanced the anastomosis device530 such that a first apposition portion 532 and a central portion 534of the anastomosis device 530 have emerged from the sheath 510. Thefirst apposition portion 532 has expanded to form a generally circulardisc. The central portion 534 has expanded to form a generallycylindrical shape with a lumen therethrough. The first appositionportion 532 is positioned in the body conduit 540. The central portion534 is positioned in the opening 560.

In FIG. 5E, the anastomosis device 530 has been fully deployed from thesheath 510 so as to create the anastomosis between the body conduits 540and 550. The first apposition portion 532 is positioned in the bodyconduit 540. The second apposition portion 536 is positioned in the bodyconduit 550. The central portion 534 is positioned in the opening 560between the first and second apposition portions 532 and 536. The firstand second apposition portions 532 and 536 exert

apposition forces to the respective tissue surfaces surrounding theopening 560. The central portion 534 maintains an open tunnel orpassageway between the body conduits 540 and 550 to allow material flowtherebetween.

In some embodiments, the anastomosis device 530 and other deviceembodiments provided herein are repositionable and/or retrievable afterdeployment. Therefore, if the initial deployment is deemeddissatisfactory, the anastomosis device 530 can be fully or partiallyretrieved into the sheath 510 and redeployed to a more desirableposition.

The design of the anastomosis device 530 facilitates a durable patentanastomosis between the body conduits 540 and 550, notwithstanding thefact that some anatomical environments in which the anastomosis device530 may be used are dynamic, such as the dynamic peristaltic motionenvironment of the GI tract. The anastomosis device 530 includes designfeatures that facilitate resilient patency even in such dynamicenvironments. For example, the anastomosis device 530 is highly flexibleand therefore highly conformable to irregular tissue topography anddynamic tissue topography. Furthermore, the apposition forces providedby the first apposition portion 532 and the second apposition portion536 are substantially independent of the in situ device shape and/ordiameter. In some embodiments, one or more auxiliary tissue anchoragefeatures (e.g., anchors, barbs, protrusions, atraumatic members, and/orpenetrating members, and combinations thereof) are included on theanastomosis device 530. Such anchorage features can provide increasedfixation and to resistance to migration of the anastomosis device 530within the body.

In some embodiments the anastomosis device 530 will be implanted in apatient for a temporary period of time. Anastomosis device 530 may beused, for example, to provide time to allow the tissues of the bodyconduits 540 and 550 to grow together to form a tissue anastomosis, andthen the anastomosis device 530 can be removed. Therefore, in some suchcases the anastomosis device 530 and other embodiments described hereincan be deployed at the site of the anastomosis and later removed. Insome embodiments, the anastomosis device 530, or portions thereof, arebioabsorbable such that some or all of the structure of the anastomosisdevice 530 will deteriorate in time. For example, in some suchembodiments portions of the frame may deteriorate by bioabsorption,after which other portions of the anastomosis device 530 may benaturally expelled from the GI tract, or otherwise retrieved. In somecases, the elongate member may need to be severed in one or morelocations prior to removal from the body. That may the case, forexample, when tissue growth has engulfed portions of the elongatemember.

When retrieval of an anastomosis device, such as anastomosis device 530,from the body is desired, a retrieval sheath containing a grasping toolcan be routed to the location of the anastomosis device in the patient'sbody. The grasping tool can be used to temporarily couple with theelongate member of the anastomosis device, such as a wire loop 122 or142 of example frame 100. The grasping tool can then be retracted intothe retrieval sheath. As the grasping tool is retracted into theretrieval sheath, the elongate member will begin to be drawn into thedistal end of the retrieval sheath. In some embodiments, a funnel isincluded on the distal end portion of the retrieval sheath. The funnelwill provide a wider initial opening at the distal tip of the retrievalsheath to facilitate the capture of all portions of the anastomosisdevice. As the grasping tool is further retracted, the entireanastomosis device can be pulled into the lumen of the retrieval sheath.Then the retrieval sheath, containing the anastomosis device, can thenbe removed from the patient.

In another example configuration of some embodiments of the anastomosisdevices provided herein, the devices can be configured to occlude/seal adefect in the wall of a body lumen such as an intestine or blood vessel.In such a case, the anastomosis device includes a covering material thatis arranged such that materials are inhibited or prevented from passingthrough the anastomosis device. The portion of the anastomosis devicewith the covering material is positioned on the inside of the bodylumen. In that orientation, materials that are contained within the bodylumen are occluded, i.e., prevented or inhibited from leaking from thebody lumen. In addition, in that orientation the anastomosis deviceprovides separation of intralumenal materials from the defect in thebody lumen wall. The separation can, in some scenarios, allow healing ofthe defect, because contact of the biomaterials to the defect may tendto inhibit or prevent the healing process of the tissue surrounding thedefect. For example, fecal matter within a colon would tend to inhibitthe healing process of a perforation in the colon wall. In some suchcircumstances, the anastomosis device can be temporarily implanted inthe body lumen such that the covering material overlays the perforationof the body lumen wall. After the perforation has healed and/or closed,the anastomosis device, or portions thereof, can be removed from thepatient, or in some cases the anastomosis device, or portions thereof,may be naturally expelled by the body. While in some suchimplementations the anastomosis device is implanted temporarily, in someimplementations the anastomosis device is implanted permanently.

With reference to FIGS. 6A and 6B, an example wire winding mandrel 600can be used to create some embodiments of the wire frames of theanastomosis devices provided herein. For example, the mandrel 600 can beused to create the frame 100 as shown in FIGS. 1A-3B. The windingmandrel 600 can be configured with the dimensional spacing, radii, andangles corresponding to the shape of the frame 100 as desired. Thewinding mandrel 600 can also be readily modified to create otherembodiments of frames having other configurations as desired.

In some embodiments, the mandrel 600 includes two identical endplates610 a-b and a shaft 620. The endplates 610 a-b are mounted onto theshaft 620 such that the endplates 610 a-b are oriented in oppositedirections of each other (like mirror images). Each endplate 610 a-bincludes a central bore 612 a-b and a collar 618 a-b which slidablyreceive the shaft 620. In some embodiments, the collar 618 a-b includesa locking mechanism, such as a setscrew, by which the endplates 610 a-bare releasably lockable to the shaft 620. When the individual lockingmechanisms are released, the individual endplates 610 a and/or 610 b canbe axially translated and/or rotated in relation to the shaft 620 and inrelation to each other.

The endplates 610 a-b include one or more inner hooks 614 a-b and one ormore outer arches 616 a-b. In the depicted embodiment, the endplates 610a-b each include twelve inner hooks 614 a-b and six outer arches 616a-b. Accordingly, the frame 100 that has six wire loops 122 and 142 canbe formed using the depicted endplates 610 a-b. In other embodiments ofwire winding mandrel 600, fewer than six or more than six outer arches616 a-b can be included on each endplate 610 a-b. Further, it should beunderstood that the outer arches 616 a-b and inner hooks 614 a-b can beconfigured with a variety of different geometries so that appositionfeatures (e.g., wire loops 122 and 142) having the desired shape andsize can be formed.

In some embodiments, to form the frame 100 an elongate member can bewound around a series of the inner hooks 614 a-b and outer arches 616a-b in a pattern. During the winding, the endplates 610 a-b are lockedto the shaft 620 so that they are separated from each other by anexample distance ‘z.’ In some embodiments, the winding pattern is asfollows. First, the elongate member is engaged with a first inner hook614 a of endplate 610 a. From the first inner hook 614 a, the elongatemember is wound around a first outer arch 616 a of endplate 610 a thatis in general radial alignment with the first inner hook 614 a. Afterwinding the elongate member around the first outer arch 616 a, theelongate member can be engaged with a second inner hook 614 a ofendplate 610 a that is also in general radial alignment with the firstouter arch 616 a. From the second inner hook 614 a of endplate 610 a,the elongate member is routed toward the other endplate 610 b along apath that is generally parallel to the shaft 620. At the endplate 610 b,the elongate member is engaged with a first inner hook 612 b. From thefirst inner hook 614 b, the elongate member can be wound around a firstouter arch 616 b of endplate 610 b that is in general radial alignmentwith the first inner hook 614 b. After winding the elongate memberaround the first outer arch 616 b, the elongate member can be engagedwith a second inner hook 614 b of endplate 610 b that is also in generalradial alignment with the first outer arch 616 b. From there, theelongate member can be routed back toward the endplate 610 a along apath that is generally parallel to the shaft 620. The pattern can thenbe repeated starting at a third inner hook 614 a, and so on. In someembodiments, after the completion of the winding pattern, all innerhooks 614 a-b and all outer arches 616 a-b are in contact with theelongate member. The two free ends of the elongate member can then besecured either by conjoining the ends together, or by temporarilyclamping them to the endplates 610 a-b.

During the aforementioned process of winding the elongate member ontothe wire winding mandrel 600, the endplates 610 a-b are separated fromeach other by a distance ‘z.’ After that winding process, the centralportion 130 of frame 100 is comprised of twelve linear portions ofelongate member that are generally parallel to the shaft 620 and thathave an approximate length of ‘z.’ Next, to continue the process offorming the frame 100, one of the endplates 610 a or 610 b is rotatedand translated (simultaneously) in relation to shaft 620 while the otherendplate 610 a or 610 b is maintained in a stationary position (e.g.,locked) in relation to shaft 620. Naturally, as the endplates 610 a-bare rotated in relation to each other, the elongate member portions inthe central portion 130 will cause the endplates 610 a-b to be drawntowards each other such that the separation will become less thandistance ‘z.’ That relative motion between the endplates 610 a and 610 bwill form the elongate member portions of the central portion 130 intosegments of a helix as shown in FIGS. 1A-3B. The locking mechanisms ofboth endplates 610 a-b are then activated to maintain the elongatemember in the wound configuration.

In some embodiments, after the elongate member has been wound onto thewinding mandrel 600 as described above, the assembly is heated toshape-set the elongate member to its as-wound shape. In one suchnon-limiting example, the elongate member is a NiTi wire, and the NiTiwire in a constrained state on the winding mandrel 600 is heated atabout 470° C. for about 8 minutes. In other examples, higher or lowertemperatures and shorter or longer times are used. The heating processwill cause the NiTi wire to be heat-set into the wound shape or thememory shape. Accordingly, the NiTi wire will tend to naturallyself-expand to reconfigure itself to the memory shape when deployed froma delivery sheath to a target site within a body.

While the example wire winding mandrel 600 is configured to create aframe 100 that has an angle between the first apposition portion 120 andthe central portion 130 of about 90°, and an angle between the secondapposition portion 140 and the central portion of about 90°, it shouldbe understood that mandrel 600 can be readily configured to createframes with such angles that are less than or more than 90°. Such anglescan be equal to each other or unequal to each other. Further, in someembodiments the length of the helically wound central portion 130 iscontrolled by the combination of the distance ‘z’ and the diameter ofthe elongate member. That is, to create a frame with a longer centralportion 130, a longer distance ‘z’ and/or a larger elongate memberdiameter can be selected.

While this specification contains many specific implementation details,these should not be construed as limitations on the scope of anyinvention or of what may be claimed, but rather as descriptions offeatures that may be specific to particular embodiments of particularinventions. Certain features that are described in this specification inthe context of separate embodiments can also be implemented incombination in a single embodiment. Conversely, various features thatare described in the context of a single embodiment can also beimplemented in multiple embodiments separately or in any suitablesubcombination. Moreover, although features may be described above asacting in certain combinations and even initially claimed as such, oneor more features from a claimed combination can in some cases be excisedfrom the combination, and the claimed combination may be directed to asubcombination or variation of a subcombination.

Particular embodiments of the subject matter described in thisspecification can be implemented so as to realize one or more of thefollowing advantages. In some embodiments, the anastomosis devicesprovided herein are configured to be highly conformable to thetopography of tissue surfaces. The high conformability of theanastomosis devices makes them well-suited, for example, for performinganastomoses in areas including, but not limited to, GI tract lumens.Further, the conformability of the anastomosis devices providesresilient fixation and consistent patency between anastomosed conduits,even when treating body conduits that are subject to anatomicalmovements, such as the peristaltic movements of the GI tract. Theanastomosis devices are also configured to not inhibit such anatomicalmovements. The anastomosis devices can allow the transfer of materialsthrough the lumen of the device from one body conduit to another. Insome embodiments, portions of the anastomosis device include a coveringmaterial to enhance the sealing characteristics of the device, and toinhibit tissue ingrowth to facilitate later removal of the device. Insome embodiments, the anastomosis devices provided herein are configuredto treat a wide variety of differently-sized and shaped tissues whileexerting low apposition forces to the tissue surfaces. Thus, a singledevice may offer physicians the ability to connect tissues of severaldifferent sizes and shapes. In some embodiments, the anastomosis devicesprovided herein are configured to provide a generally consistent lumendiameter that is essentially independent of the in situ length of thedevice. In some embodiments, the anastomosis devices provided herein canbe deployed to a target location within a patient's body using aminimally invasive transcatheter technique. In some embodiments, thetranscatheter deployment can be performed endoscopically orlaproscopically. In some embodiments, the anastomosis devices providedherein are repositionable and/or retrievable after deployment.

The invention of this application has been described above bothgenerically and with regard to specific embodiments. It will be apparentto those skilled in the art that various modifications and variationscan be made in the embodiments without departing from the scope of thedisclosure. Thus, it is intended that the embodiments cover themodifications and variations of this invention provided they come withinthe scope of the appended claims and their equivalents.

What is claimed is:
 1. A medical device for creating an anastomosisbetween a first body conduit and a second body conduit and configured totransition between contracted and expanded configurations, the devicecomprising: an elongate member defining a frame comprising: a firstapposition portion and a second apposition portion; and a centralportion disposed between the first apposition portion and the secondapposition portion, the central portion defining a lumen therethrough,the central portion having a first diameter and a first length in thecontracted configuration and having a second diameter and a secondlength in the expanded configuration, wherein the second length isgreater than the first length and the second diameter is the same as orless than the first diameter, and the second diameter is substantiallyconsistent along the entire second length of the central portion; and acovering material disposed on at least a portion of the central portion,the covering material being configured to allow material flow throughthe lumen and between the first body conduit and the second bodyconduit, wherein the frame is configured such that when transitioningfrom the contracted configuration to the expanded configuration, thedifference between the first length and the second length of the centralportion is configured to increase by a greater amount relative to areduction between the first diameter and the second diameter of thecentral portion.
 2. The device of claim 1, wherein the elongate membertraverses the central portion along a helical path.
 3. The device ofclaim 2, wherein the elongate member in the central portion extendsalong the helical path substantially perpendicular to a longitudinalaxis of the device when the device is in the contracted configuration.4. The device of claim 1, wherein the elongate member is a singlecontinuous elongate member.
 5. The device of claim 4, wherein the singlecontinuous elongate member is a wire.
 6. The device of claim 5, whereinthe single continuous elongate member comprises nitinol.
 7. The deviceof claim 1, wherein the elongate member has a defined length and has avariable thickness throughout the defined length.
 8. The device of claim1, wherein the first apposition portion and the second appositionportion each include diameters that exceed both the first diameter andthe second diameter of the central portion.
 9. The device of claim 1,wherein the first apposition portion includes a plurality of elongatewire loops that are each configured to bear a load without imparting asubstantial force to any other of the plurality of elongate wire loopsof the first apposition portion.
 10. The device of claim 1, wherein thesecond apposition portion includes a plurality of elongate wire loopsthat are each configured to bear a load without imparting a substantialforce to any other of the plurality of elongate wire loops of the secondapposition portion.
 11. The device of claim 1, wherein the coveringmaterial is configured to inhibit tissue ingrowth or endothelializationinto the covering material.
 12. The device of claim 1, wherein thecovering material is also disposed on at least a portion of the firstapposition portion or the second apposition portion.
 13. The device ofclaim 1, wherein the covering material comprises expandedpolytetrafluoroethylene (ePTFE).
 14. The device of claim 1, furthercomprising one or more radiopaque markers disposed on the device. 15.The device of claim 1, wherein the frame further comprises one or moretissue anchorage features.
 16. A medical device for creating ananastomosis between a first body conduit and a second body conduit andconfigured to transition between contracted and expanded configurations,the device comprising: an elongate member defining a frame comprising: afirst apposition portion and a second apposition portion; and a centralportion disposed between the first apposition portion and the secondapposition portion, the central portion defining a lumen therethroughand having a diameter, a first length in the contracted configurationand a second length in the expanded configuration, wherein the secondlength is greater than the first length, and the diameter issubstantially consistent along the entirety of the second length; and acovering material disposed on at least a portion of the central portion,the covering material being configured to allow material flow throughthe lumen and between the first body conduit and the second bodyconduit, wherein the central portion is configured such that thediameter of the central portion is substantially the same in thecontracted configuration and in the expanded configuration.
 17. Thedevice of claim 16, wherein the elongate member traverses the centralportion along a helical path.
 18. The device of claim 17, wherein theelongate member in the central portion extends along the helical pathsubstantially perpendicular to a longitudinal axis of the centralportion when the device is in the contracted configuration.
 19. Thedevice of claim 16, wherein the elongate member consists of a continuouswire.
 20. The device of claim 19, wherein the continuous wire includesfirst and second ends that are coupled together.
 21. The device of claim19, wherein the elongate member comprises nitinol.
 22. The device ofclaim 16, wherein adjacent helical portions of the central portion ofthe elongate member contact one another in the contracted configuration.23. The device of claim 16, wherein a transition from the contractedconfiguration to the expanded configuration includes a substantiallygreater longitudinal extension of the central portion than a diametricalreduction of the diameter of the central portion.